Manually operated sheet product dispensers are commonly used for dispensing sheet product strips like paper sheets such as paper towels, facial tissue, or the like. Such sheet product strips strongly differ in properties such as thickness and surface roughness so that sheet products differ strongly in their sliding properties and their tensile strength when used with a provided dispenser.
Dispensers usually comprise a housing in which a source of sheet product, e.g. a paper roll or a stack of a continuous paper strip, is accommodated. In cases where the source of sheet product is a continuous strip of paper sheets, the single sheets are attached to one another by a perforation line transverse to the strip direction in order to facilitate sheet tearing.
Manually operated dispensers are usually mounted on a wall. For dispensing the sheet product, these dispensers have a dispenser opening located in the bottom of the dispenser through which the sheet product strip is guided to the exterior of the housing.
A center feed toilet paper dispenser is known from WO 98/25848. This dispenser holds the toilet paper in a stationary position as the loose paper and is pulled from the inner core of the paper roll. A housing for containing the paper roll is attached to a base and a cover engaged with the housing compresses the paper roll against the base. This compression prevents sag of the layered toilet paper roll as the void in the paper core became enlarged.
There are various known types of dispenser openings which differ substantially in the frictional force applied to the sheet product during dispensing. One type of dispenser opening comprises a sharp edge that is used for detaching suitably sized perforated sheets. In this context, US 2008/0290210 A1 discloses a dispenser opening in which the sheet product passes through a Z-shaped path, which causes the sheet product to break as desired. The dispenser opening is attached such that it is free to pivot along two axes to avoid any extreme deflection of the sheet product strip at the opening edge.
Other approaches are directed to reducing frictional force on the sheet product. For example, U.S. Pat. No. 5,141,171 A discloses an opening with a mouthpiece which is mounted pivotally about one axis such that the dispensing direction of the opening can be partially adjusted to accommodate an inclined pulling direction of a consumer.
One issue that may arise for such a dispenser opening is that a frictional force applied to the sheet product strip during dispensing is inadequate which results in individual sheets becoming difficult to tear off. Another issue that may arise is that the frictional force becomes too great which results in the sheet product being separated into unsuitable small pieces upon pulling or the leading edge of the sheet product remaining within or even being pulled back into the dispenser housing, leaving it difficult to reach for the user.
The same is true for the design of the dispenser opening. A deflection at the opening edge that applies a tensile force above the breaking force of the strip could lead to a breaking of the sheet product strip at the corresponding perforation line right at the opening edge. This may result in difficulties for the next user of the dispenser to grab the strip's end to pull out the next sheet, especially if the opening is too small to grasp the strip's end lost therein.